Humidification cylinder and method of humidifying material

ABSTRACT

A humidifying cylinder includes a first rotatable cylinder having an inlet end and an outlet end and a plurality of first blades extending substantially radially outwardly from an exterior surface of the first cylinder. The humidifying cylinder further includes a second rotatable cylinder having an inlet end and an outlet end and a plurality of second blades extending substantially radially inwardly from an interior surface of the second cylinder, the second cylinder being substantially coaxial with the first cylinder and the first cylinder being disposed inside of the second cylinder such that the exterior surface of the first cylinder and the interior surface of the second cylinder define an annular space. At least one drive is provided for rotating the first cylinder and the second cylinder. At least one conduit is disposed in the annular space for introducing moisture into the annular space. A method of humidifying material is also disclosed.

FIELD OF THE INVENTION

[0001] The present invention relates to a humidification ormoisturization device and method, more particularly, to a device and amethod for humidifing or moisturizing tobacco.

BACKGROUND AND SUMMARY

[0002] It is often necessary to humidify or moisten dry particulatematerials prior to further use of the materials. For example, expandedtobacco is typically reordered by permitting the tobacco particles toreside in a humid atmosphere or by conveying the tobacco particles on aconveyor through a humid atmosphere for a necessary period of time.Unless the tobacco is moved about through the humid atmosphere, theresidence time in the humid atmosphere can be prohibitively timeconsuming.

[0003] Equipment such as the rotary tobacco treatment cylinder disclosedin U.S. Pat. No. 5,425,384 can be used to rapidly reorder tobacco. Oneproblem with such equipment is that, when the cylinder is too large, ittends to degrade the tobacco particles because the particles fall fromblades on the interior of the cylinder to the bottom of the cylinderover a great distance. When the cylinder is made smaller, the capacityof the cylinder is reduced. It is desirable to provide a reorderingdevice that permits rapid reordering of large quantities of tobaccowhile minimizing degradation of the tobacco.

[0004] In accordance with one aspect of the present invention, ahumidifying cylinder includes a first rotatable cylinder having an inletend and an outlet end and a plurality of first blades extendingsubstantially radially outwardly from an exterior surface of the firstcylinder. The humidifying cylinder further includes a second rotatablecylinder having an inlet end and an outlet end and a plurality of secondblades extending substantially radially inwardly from an interiorsurface of the second cylinder, the second cylinder being substantiallycoaxial with the first cylinder and the first cylinder being disposedinside of the second cylinder such that the exterior surface of thefirst cylinder and the interior surface of the second cylinder define anannular space. At least one drive is provided for rotating the firstcylinder and the second cylinder. At least one conduit is disposed inthe annular space for introducing moisture into the annular space. Amethod of humidifying material is also disclosed.

[0005] In accordance with another aspect of the present invention, amethod of humidifying material is disclosed. According to the method,material is introduced into an annular space between a first rotatablecylinder having an inlet end and an outlet end and a plurality of firstblades extending substantially radially outwardly from an exteriorsurface of the first cylinder and a second rotatable cylinder having aninlet end and an outlet end and a plurality of second blades extendingsubstantially radially inwardly from an interior surface of the secondcylinder, the second cylinder being substantially coaxial with the firstcylinder and the first cylinder being disposed inside of the secondcylinder such that the exterior surface of the first cylinder and theinterior surface of the second cylinder define the annular space. Thefirst cylinder and the second cylinder are rotated such that, as thesecond cylinder is rotated, material falls from at least some of thesecond blades onto the first cylinder and, as the first cylinderrotates, material falls from at least some of the first blades onto thesecond cylinder. Material is conveyed in the annular space from theinlet end of the first cylinder and the inlet end of the second cylindertoward the outlet end of the first cylinder and the outlet end of thesecond cylinder. Moisture is applied to material in the annular space.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The features and advantages of the present invention are wellunderstood by reading the following detailed description in conjunctionwith the drawings in which like numerals indicate similar elements andin which:

[0007]FIG. 1 is a schematic, cross-sectional side view of a humidifyingcylinder according to an embodiment of the present invention;

[0008]FIG. 2 is a schematic, cross-sectional view of the humidifyingcylinder of FIG. 1 taken at Section 2-2; and

[0009]FIG. 3 is a schematic, cross-sectional side view of a humidifyingcylinder according to another embodiment of the present invention.

DETAILED DESCRIPTION

[0010] A humidifying cylinder 21 according to an embodiment of thepresent invention is seen in FIG. 1 and FIG. 2, showing the humidifyingcylinder in longitudinal cross-section and axial cross-section. Forpurposes of the present invention, the words humidification andmoisturization will be used substantially interchangeably to convey thegeneral notion of applying moisture to dry material, such as duringreordering of tobacco. The cylinder 21 and method according to thepresent invention are preferably used to reorder tobacco, morepreferably expanded tobacco, from 1% OV (oven volatiles) to 20% OV,although it is contemplated that the cylinder will be useful inincreasing the moisture of a number of other different products, such asincreasing moisture from bone dry to 50% moisture. For purposes of thepresent application, % moisture may be considered to be equivalent tooven volatiles (OV) as explained in U.S. Pat. No. 4,202,357, which isincorporated by reference.

[0011] The humidifying cylinder 21 includes a first rotatable cylinder23 having an inlet end 25 and an outlet end 27 and a plurality of firstblades 29 extending substantially radially outwardly from an exteriorsurface 31 of the first cylinder. If desired or necessary, the firstcylinder 23 may be in the form of a plurality of blades connected at anaxis of the first cylinder, without providing an actual cylinder towhich the blades are attached.

[0012] The humidification cylinder 21 further includes a secondrotatable cylinder 33 having an inlet end 35 and an outlet end 37 and aplurality of second blades 39 extending substantially radially inwardlyfrom an interior surface 41 of the second cylinder. The second cylinder33 is preferably substantially coaxial with the first cylinder 23. Thefirst cylinder 23 is disposed inside of the second cylinder 33 such thatthe exterior surface 31 of the first cylinder and the interior surface41 of the second cylinder define an annular space 43.

[0013] At least one drive 45 is provided for rotating the first cylinder23 and the second cylinder 33. Preferably, the drive 45 includes asingle motor, such as an electric motor, arranged to drive both thefirst cylinder 23 and the second cylinder 33 using means such as gears,chains, belts, and the like. The first cylinder 23 and the secondcylinder 33 can be rigidly connected to each other, such as by barsdisposed at interior points of the cylinders, to facilitate driving thecylinders with a common drive, or may be driven by a common drive thatdrives rotatable supports, such as is disclosed in U.S. Pat. No.5,425,384, which is incorporated by reference. If desired or necessary,as seen in FIG. 3, separate drives 45 a and 45 b can be provided fordriving the first cylinder 23 and the second cylinder 33 (shown withoutother features shown in FIGS. 1 and 2 for sake of clarity). In allembodiments of the present invention, the first cylinder 23 and thesecond cylinder 33 are preferably driven in the same direction ofrotation, however, if desired or necessary, the first cylinder and thesecond cylinder may be driven in opposite directions of rotation.

[0014] The humidification cylinder 21 includes at least one, preferablya plurality of conduits 47 disposed in the annular space 43 forintroducing moisture into the annular space. The conduits 47 arepreferably pipes connected to a source of moisture 49 such as water anda pump 51 for forcing the water through the conduits 47 under pressure.The conduits 47 preferably include a plurality of nozzles 53 arrangedalong their length so that, when moisture under pressure is pumpedthrough the conduits, the moisture is introduced into the annular space43 in the form of atomized droplets. If desired or necessary, themoisture may be introduced into the annular space 43 in the form ofmoisture streams or cascades, or by other means than through conduits inthe annular space, such as through openings in the first or secondcylinders. The moisture is preferably introduced at substantiallyambient temperatures, however, if desired or necessary, the moisture maybe introduced in the form of steam.

[0015] The conduit or conduits 47 may be provided with nozzles forintroducing moisture in different amounts in different regions of theannular space 43. For example, the nozzles 53 may be larger toward theinlet ends of the cylinders 23 and 33 so that more or less moisture maybe introduced at the inlet ends of the cylinders where material 55 isinitially introduced than at other regions of the annular space, asdesired or necessary for a particular application. When moisturizingexpanded tobacco, it may be desirable to introduce more moisture at aninlet end of the humidifying cylinder 21 than elsewhere in the cylinderto minimize problems with degradation of the tobacco due to the rotationof the first and second cylinders 23 and 33. Instead of conduits thatintroduce moisture continuously over their length or at different pointsalong the entire length of the annular space 43, conduits may introducemoisture at particular points or continuously or discontinuously overlimited lengths of the annular space, and multiple conduits may beprovided to introduce moisture at different rates over the length of theannular space, as desired or necessary.

[0016] The inlet end 25 of the first cylinder 23 and the inlet end 35 ofthe second cylinder 33 are preferably disposed vertically above theoutlet end 27 of the first cylinder 23 and the outlet end 37 of thesecond cylinder 33, respectively. In this way, material 55 introducedinto the annular space 43 at the inlet ends of the first cylinder 23 andthe second cylinder 33 is conveyed toward the outlet ends of thecylinders under gravity and then, preferably, falls out of the annularspace for further operations.

[0017] As seen in FIG. 2, some or all of the first blades 29 and some orall of the second blades 39 may be bent to optimize operationalcharacteristics such as the angle of rotation of the blades relative toa horizontal plane at which material 55 cascades from the blades to alower point in the annular space during rotation of the first and secondcylinders 23 and 33. U.S. Pat. No. 5,425,384 discloses bending blades ina rotatable tobacco treatment cylinder to control the release of tobaccofrom blades on an interior surface of the cylinder and is incorporatedby reference.

[0018] The first cylinder 23, the first blades 29, the second cylinder33, and the second blades 39 are preferably sized such that, when thefirst cylinder and the second cylinder are rotated, material 55 fallsfrom second blades onto the first cylinder and then falls from firstblades onto the second cylinder. Preferably, all of the material 55falling from the second blades 39 falls onto the first cylinder 23before falling onto the second cylinder, however, it is anticipatedthat, in normal operation, some material will fall directly from thesecond blades 39 to a bottom point of the second cylinder without firstfalling onto the first cylinder and that, for some applications of thehumidifying cylinder, this may be a desirable result. When reorderingtobacco, it is presently believed that it will generally be desirablefor all tobacco falling from the second blades 39 to first fall onto thefirst cylinder 23 and then, after further rotation of the firstcylinder, to a lower level of the second cylinder. Thus, according tothe present invention, problems with degradation of the tobacco areminimized by reducing the distance that the tobacco falls each time thatit falls from the second blades 39, at least as compared to rotatingcylinder humidification devices in which no first cylinder is provided.

[0019] It is presently preferred that the first and second cylinders 23and 33 will each be about 15′-25′(4.57 m to 7.62 m) in length, that thefirst cylinder 23 will have an exterior diameter of about 1′-4′(0.30 mto 1.22 m), that the second cylinder 33 will have an interior diameterof about 3′-8′(0.91 m to 2.44 m).

[0020] A method of humidifying material 55 according to the presentinvention is described in connection with the cylinder 21 shown in FIGS.1 and 2. According to the method, material 55 is introduced into theannular space 43 between the first rotatable cylinder 23 and the secondrotatable cylinder 33. The first cylinder 23 and the second cylinder 33are rotated such that, as the second cylinder is rotated, material 55falls from at least some of the second blades 39, i.e., the blades thathave rotated with the second cylinder toward an upper region of thesecond cylinder beyond a horizontal plane, onto the first cylinder and,as the first cylinder rotates, material falls from at least some of thefirst blades 29 back onto the second cylinder, i.e., a lower region ofthe second cylinder.

[0021] Material 55 in the annular space 43 is conveyed from the inletend 25 of the first cylinder 23 and the inlet end 35 of the secondcylinder 33 toward the outlet end 27 of the first cylinder and theoutlet end 37 of the second cylinder by gravity by arranging the inletends of the first and second cylinders vertically above the outlet ends.If desired or necessary, the material 55 may be conveyed by shaping theblades 29 and 39 as screws so that the material is conveyed as in ascrew conveyor in addition to or instead of conveying the material bygravity.

[0022] Moisture is applied to material 55 in the annular space 43 as itis conveyed from the inlet ends of the cylinders toward the outlet ends.Preferably, the moisture is applied through nozzles 53 on conduits 47pumped by a pump 51 from a source of moisture 49 into the annular space43. By manipulating the characteristics of the moisture deliveryequipment, such as by selecting different sizes and characteristics fornozzles 53 and by placing conduits 47 at different locations throughoutthe annular space 43, different amounts of moisture are preferablyapplied to the material 55 at different locations in the annular space.The moisture is preferably applied to the material 55 in the annularspace 43 as atomized droplets, preferably at ambient or normal roomtemperature, although, for some applications it may be desirable tointroduce moisture in the form of a stream or sheet or cascade ofmoisture or in the form of steam.

[0023] The first cylinder 23 and the second cylinder 33 are preferablyrotated by a common drive 45, in the same direction of rotation, and atthe same rotational speed. As shown in FIG. 3, however, the firstcylinder 23 may be rotated by a first drive 45 a and the second cylinder33 may be rotated by a second drive 45 b. Again, the first cylinder 23and the second cylinder 33 are preferably rotated in the same rotationaldirection, and at the same rotational speed. In the embodiment of FIGS.1 and 2 and in the embodiment of FIG. 3, however, it will be appreciatedthat, by appropriate gearing or arrangement of the drives, the firstcylinder 23 and the second cylinder 33 may be rotated in differentrotational directions and/or at different rotational speeds.

[0024] While this invention has been illustrated and described inaccordance with a preferred embodiment, it is recognized that variationsand changes may be made therein without departing from the invention asset forth in the claims.

What is claimed is:
 1. A humidifying cylinder, comprising: a firstrotatable cylinder having an inlet end and an outlet end and a pluralityof first blades extending substantially radially outwardly from anexterior surface of the first cylinder; a second rotatable cylinderhaving an inlet end and an outlet end and a plurality of second bladesextending substantially radially inwardly from an interior surface ofthe second cylinder, the second cylinder being substantially coaxialwith the first cylinder and the first cylinder being disposed inside ofthe second cylinder such that the exterior surface of the first cylinderand the interior surface of the second cylinder define an annular space;at least one drive for rotating the first cylinder and the secondcylinder; and at least one conduit disposed in the annular space forintroducing moisture into the annular space.
 2. The humidifying cylinderas set forth in claim 1 , wherein the at least one conduit includesopenings for introducing moisture at different locations in the annularspace.
 3. The humidifying cylinder as set forth in claim 2 , wherein theat least one conduit permits introduction of different amounts ofmoisture at the different locations in the annular space.
 4. Thehumidifying cylinder as set forth in claim 1 , wherein the at least oneconduit includes nozzles for introducing moisture as atomized droplets.5. The humidifying cylinder as set forth in claim 1 , wherein the atleast one drive includes a single motor arranged to drive both the firstcylinder and the second cylinder.
 6. The humidifying cylinder as setforth in claim 5 , wherein the at least one drive is arranged to drivethe first cylinder and the second cylinder in a same direction ofrotation.
 7. The humidifying cylinder as set forth in claim 1 , whereinthe at least one drive is arranged to drive the first cylinder and thesecond cylinder in a same direction of rotation.
 8. The humidifyingcylinder as set forth in claim 1 , wherein the at least one driveincludes a first drive for driving the first cylinder and a second drivefor driving the second cylinder.
 9. The humidifying cylinder as setforth in claim 8 , wherein the at least one drive is arranged to drivethe first cylinder and the second cylinder in a same direction ofrotation.
 10. The humidifying cylinder as set forth in claim 1 , whereinthe inlet end of the first cylinder and the inlet end of the secondcylinder are disposed vertically above the outlet end of the firstcylinder and the outlet end of the second cylinder, respectively. 11.The humidifying cylinder as set forth in claim 1 , wherein the firstcylinder, the first blades, the second cylinder, and the second bladesare sized such that, when the first cylinder and the second cylinder arerotated, material falls from second blades onto the first cylinder andthen falls from first blades onto the second cylinder.
 12. A method ofhumidifying material, comprising the steps of: introducing material intoan annular space between a first rotatable cylinder having an inlet endand an outlet end and a plurality of first blades extendingsubstantially radially outwardly from an exterior surface of the firstcylinder and a second rotatable cylinder having an inlet end and anoutlet end and a plurality of second blades extending substantiallyradially inwardly from an interior surface of the second cylinder, thesecond cylinder being substantially coaxial with the first cylinder andthe first cylinder being disposed inside of the second cylinder suchthat the exterior surface of the first cylinder and the interior surfaceof the second cylinder define the annular space; rotating the firstcylinder and the second cylinder such that, as the second cylinder isrotated, material falls from at least some of the second blades onto thefirst cylinder and, as the first cylinder rotates, material falls fromat least some of the first blades onto the second cylinder; conveyingmaterial in the annular space from the inlet end of the first cylinderand the inlet end of the second cylinder toward the outlet end of thefirst cylinder and the outlet end of the second cylinder; and applyingmoisture to material in the annular space.
 13. The method as set forthin claim 12 , wherein different amounts of moisture are applied to thematerial at different locations in the annular space.
 14. The method asset forth in claim 12 , wherein moisture is applied to the material inthe annular space as atomized droplets.
 15. The method as set forth inclaim 12 , wherein the first cylinder and the second cylinder arerotated by a common drive.
 16. The method as set forth in claim 15 ,wherein the first cylinder and the second cylinder are rotated in a samedirection.
 17. The method as set forth in claim 12 , wherein the firstcylinder is rotated by a first drive and the second cylinder is rotatedby a second drive.
 18. The method as set forth in claim 17 , wherein thefirst cylinder and the second cylinder are rotated in a same direction.19. The method as set forth in claim 12 , wherein the first cylinder andthe second cylinder are rotated at a same rotational speed.
 20. Themethod as set forth in claim 12 , wherein material is conveyed in theannular space from the inlet end of the first cylinder and the inlet endof the second cylinder toward the outlet end of the first cylinder andthe outlet end of the second cylinder by gravity.